Computers use numerous memory units such as Dynamic Random Access Memory units (DRAM)s for the storage of and retrieval of data. Initially computers used individual memory units mounted directly onto the computers main board generally known as the mother board or system board. As computers increased in size and complexity, they required more and more memory and the system boards could not accommodate a sufficient number of individual memory units. An early solution to this problem was to create a memory module, known as Single In-line Memory Module (SIMM), that was formed of a plurality of individual memory units arranged in banks and mounted on a card in electrical connection to terminal pads displayed adjacent a longitudinal edge of the card.
Still higher memory demands in the systems were met by the development of the so-called Dual In-line Memory Modules (DIMMs) having individual memory units mounted on a card in electrical connection to terminal pads displayed adjacent both sides of the pad edge to thereby accommodate increased memory units.
As computers continued to increase in complexity, additional needs such as higher speeds, greater loading and more compact board design were required. With these additional needs, some computer designs required buffers in the memory modules to recondition the computer's data or signal lines, so as to secure proper functioning of the DRAMs. To assure that systems requiring buffered modules could only be supplied with a buffered module, the modules and their respective adapter sockets, were keyed to accept only the correct type of module card. That is, to accept only buffered modules without accepting unbuffered modules or vice versa.
Because of the wide variety in computer needs, it is not uncommon for manufacturers to design some computers that require buffered modules and other computers that do not, which requires that the manufacture stock different parts to provide both buffered and unbuffered modules. In turn, as the number of required parts increase, inventory and tracking problems also increase. Moreover multiple parts, especially when similar, can cause confusion during both manufacture of the initial computer and repair of the computer in the field.